Since a low-noise automobile such as a hybrid vehicle, an electric vehicle, and a fuel cell vehicle is driven by electric motors, travelling sound thereof is smaller than that of an automobile driven only by an internal combustion engine with petroleum oil. Accordingly, a risk increases to cause an accident due to unexpected rushing-out of a pedestrian therearound as being not aware of proximity of an automobile.
To solve such a problem, there has been known an electric vehicle that notifies a pedestrian existing at the front in a travelling direction of proximity of an automobile by operating a speaker with a detection output of a detector when the pedestrian is detected by the detector (e.g., see Patent Literature 1).
There has been also known a proximity warning sound emitting device that emits proximity warning sound in accordance with a direction of a detected pedestrian with speakers arranged on the right and left of each of the front and rear of an automobile (e.g., see Patent Literature 2).